jQuery.extend({
    createUploadIframe: function (id, uri) {
        //create frame  
        var frameId = 'jUploadFrame' + id;
        var iframeHtml = '<iframe id="' + frameId + '" name="' + frameId + '" style="position:absolute; top:-9999px; left:-9999px"';
        if (window.ActiveXObject) {
            if (typeof uri == 'boolean') {
                iframeHtml += ' src="' + 'javascript:false' + '"';
            } else if (typeof uri == 'string') {
                iframeHtml += ' src="' + uri + '"';
            }
        }
        iframeHtml += ' />';
        jQuery(iframeHtml).appendTo(document.body);
        return jQuery('#' + frameId).get(0);
    },
    createUploadForm: function (id, fileElementId, data) {
        //Create form  
        var formId = 'jUploadForm' + id;
        var fileId = 'jUploadFile' + id;
        var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
        //Handle files  
        if (typeof (fileElementId) == "string") {
            fileElementId = [fileElementId];
        }
        for (var i in fileElementId) {
            var oldElement = jQuery('#' + fileElementId[i]);
            var newElement = jQuery(oldElement).clone();
            jQuery(oldElement).attr('id', fileId);
            jQuery(oldElement).before(newElement);
            jQuery(oldElement).appendTo(form);
        }
        //Handle data  
        if (data) {
            for (var i in data) {
                jQuery('<textarea name="' + i + '" style="display:none;">' + data[i] + '</textarea>').appendTo(form);
            }
        }
        //Set attributes  
        jQuery(form).css('position', 'absolute');
        jQuery(form).css('top', '-1200px');
        jQuery(form).css('left', '-1200px');
        jQuery(form).appendTo('body');
        return form;
    },

    ajaxFileUpload: function (s) {
        // introduce global settings, allowing the client to modify them for all requests, not only timeout  
        s = jQuery.extend({}, jQuery.ajaxSettings, s);
        var id = new Date().getTime();
        var form = jQuery.createUploadForm(id, s.fileElementId, (typeof (s.data) == 'undefined' ? false : s.data));
        var io = jQuery.createUploadIframe(id, s.secureuri);
        var frameId = 'jUploadFrame' + id;
        var formId = 'jUploadForm' + id;
        // Watch for a new set of requests  
        if (s.global && !jQuery.active++) {
            jQuery.event.trigger("ajaxStart");
        }
        var requestDone = false;
        // Create the request object  
        var xml = {};
        if (s.global)
            jQuery.event.trigger("ajaxSend", [xml, s]);
        // Wait for a response to come back  
        var uploadCallback = function (isTimeout) {
            var io = document.getElementById(frameId);
            try {
                if (io.contentWindow) {
                    xml.responseText = io.contentWindow.document.body ? jQuery('<div>').html(io.contentWindow.document.body.innerHTML).text() : null;
                    xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument : io.contentWindow.document;
                } else if (io.contentDocument) {
                    xml.responseText = io.contentWindow.document.body ? jQuery('<div>').html(io.contentWindow.document.body.innerHTML).text() : null;
                    xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument : io.contentDocument.document;
                }
            } catch (e) {
                jQuery.handleError(s, xml, null, e);
            }
            if (xml || isTimeout == "timeout") {
                requestDone = true;
                var status;
                try {
                    status = isTimeout != "timeout" ? "success" : "error";
                    // Make sure that the request was successful or notmodified  
                    if (status != "error") {
                        // process the data (runs the xml through httpData regardless of callback)  
                        var data = jQuery.uploadHttpData(xml, s.dataType);
                        // If a local callback was specified, fire it and pass it the data  
                        if (s.success)
                            s.success(data, status);
                        // Fire the global callback  
                        if (s.global)
                            jQuery.event.trigger("ajaxSuccess", [xml, s]);
                    } else
                        jQuery.handleError(s, xml, status);
                } catch (e) {
                    status = "error";
                    jQuery.handleError(s, xml, status, e);
                }
                // The request was completed  
                if (s.global)
                    jQuery.event.trigger("ajaxComplete", [xml, s]);
                // Handle the global AJAX counter  
                if (s.global && !--jQuery.active)
                    jQuery.event.trigger("ajaxStop");
                // Process result  
                if (s.complete)
                    s.complete(xml, status);
                jQuery(io).unbind();
                setTimeout(function () {
                    try {
                        jQuery(io).remove();
                        jQuery(form).remove();
                    } catch (e) {
                        jQuery.handleError(s, xml, null, e);
                    }
                }, 100);
                xml = null;
            }
        };
        // Timeout checker  
        if (s.timeout > 0) {
            setTimeout(function () {
                // Check to see if the request is still happening  
                if (!requestDone) uploadCallback("timeout");
            }, s.timeout);
        }
        try {
            var form = jQuery('#' + formId);
            jQuery(form).attr('action', s.url);
            jQuery(form).attr('method', 'POST');
            jQuery(form).attr('target', frameId);
            if (form.encoding) {
                jQuery(form).attr('encoding', 'multipart/form-data');
            } else {
                jQuery(form).attr('enctype', 'multipart/form-data');
            }
            jQuery(form).submit();

        } catch (e) {
            jQuery.handleError(s, xml, null, e);
        }
        jQuery('#' + frameId).load(uploadCallback);
        return {
            abort: function () {
            }
        };

    },
    uploadHttpData: function (r, type) {
        var data = !type;
        data = type == "xml" || data ? r.responseXML : r.responseText;
        // If the type is "script", eval it in global context  
        if (type == "script")
            jQuery.globalEval(data);
        // Get the JavaScript object, if JSON is used.  
        if (type == "json")
            eval("data = " + data);
        // evaluate scripts within html  
        if (type == "html")
            jQuery("<div>").html(data).find('script').remove();
        return data;
    },
    handleError: function (s, xml, status, e) {
        // If a local callback was specified, fire it  
        if (s.error)
            s.error(xml, status, e);
        // Fire the global callback  
        if (s.global)
            jQuery.event.trigger("ajaxError", [xml, s, e]);
    }
});  